User manual HANNA INSTRUMENTS HI 2221

[. . . ] Instruction Manual HI 2221 HI 2223 pH/mV/ºC Bench Meters with Calibration Check w w w. c o m 1 Dear Customer, Thank you for choosing a Hanna Instruments product. Please read this instruction manual carefully before using these instruments. This manual will provide you with the necessary information for correct use of these instruments, as well as a precise idea of their versatility. [. . . ] 18 7. 13 7. 10 7. 07 7. 05 7. 03 7. 01 7. 00 6. 99 6. 98 6. 98 6. 98 6. 98 6. 98 6. 99 6. 99 7. 00 7. 01 7. 02 7. 03 7. 04 9. 46 9. 39 9. 33 9. 27 9. 22 9. 18 9. 14 9. 11 9. 07 9. 04 9. 01 8. 99 8. 97 8. 95 8. 93 8. 91 8. 89 8. 87 8. 85 8. 83 10. 45 10. 32 10. 24 10. 18 10. 12 10. 06 10. 01 9. 96 9. 92 9. 88 9. 85 9. 82 9. 79 9. 77 9. 76 9. 75 9. 74 9. 74 9. 74 9. 75 9. 76 13. 38 13. 18 12. 99 12. 80 12. 62 12. 45 12. 29 12. 13 11. 98 11. 83 11. 70 11. 57 11. 44 11. 32 11. 21 11. 10 11. 00 10. 91 10. 82 10. 73 During calibration the instrument will display the pH buffer value at 25 ºC. 17 GOOD LABORATORY PRACTICE (GLP) GLP is a set of functions that allows the storage and retrieval of data regarding the maintenance and status of the electrode. All data regarding the last calibration is stored for the user to review when necessary. EXPIRED CALIBRATION These instruments allow the user to set the number of days before the next required calibration. The "CAL DUE" tags will blink to warn the user that the instrument should be recalibrated. For example, if a 4 days time out has been selected, the instrument will issue the alarm exactly 4 days after the last calibration. to 5 days), then the alarm will be immediately recalculated and appear 5 days after the last calibration. Notes: · If the instrument was not calibrated, or if the calibration history was deleted, the "CAL DUE" message will be displayed even if this feature is disabled in the SETUP menu. · If the instrument was calibrated using an electrode with pin and the electrode is changed with an electrode without pin or vice-versa "CAL DUE" will blink. p H CALIBRATION DATA Calibration data is stored automatically after a successful calibration. To view the pH calibration data, press the GLP key when the instrument is in pH measuring mode. Use the ARROW keys to scroll through the calibration data: · The time (hh:mm). · The date (yyyy / mm. dd). 18 · The pH calibration offset. · The pH calibration slope in mV/pH normalized to 25 °C (the percentage is referred to the ideal value of 59. 16 mV/pH). Note: If you calibrate using electrodes with pin the electrode condition and response gauges appear while the offset and slope are displayed. · The pH calibration buffers in calibrating order and with the selected resolutions used during calibration. The first pH calibration buffer: The second pH calibration buffer: The third pH calibration buffer: The fourth pH calibration buffer: The fifth pH calibration buffer: Note: The "OLd" message displayed beside the pH value means that this buffer was not used during last calibration. Press and hold down SETUP if you want to see calibration date (or time, if old calibration was performed on the same day as the current calibration). 19 · If "no bUF" message appears on the LCD, the instrument informs you that the calibration was performed with less than five buffers. · Calibration Expiration status: - if disabled. - or the number of days until the calibration alarm will be displayed, - or if expired (7 days ago). · The instrument ID. Notes: · Press GLP to return to measurement mode. · If calibration has not been performed, the instruments display "no CAL" message blinking. 20 LOGGING Up to 100 (HI 2221) or 500 (HI 2223) logged samples can be stored in memory. LOGGING THE CURRENT DATA To store the current reading into memory press the LOG key while in measuring mode. The instrument will display the current date (mm. dd) on the primary LCD, the record number on the secondary LCD and the "LOG" tag will blink for a few seconds (see example below: record No. 27 dated July 14): If there are less than 5 memory locations remaining, the record number and the "Lo" message will be displayed to alert the user. If the log space is full, the "FULL LOG" message will be displayed and no more data will be saved. Along with the current measurement, the date, time, mV value, temperature and calibration data is stored. VIEW LOGGED DATA Press RCL while in measurement mode to retrieve the stored information. [. . . ] In addition, the response time will suffer to a greater degree at temperatures below 25 ºC. TEMPERATURE CORRELATION FOR p H SENSITIVE GLASS Since the resistance of the pH electrode is in the range of 50 ­ 200 Mohm, the current across the membrane is in the pico Ampere range. Large currents can disturb the calibration of the electrode for many hours. For these reasons high humidity environments, short circuits and static discharges are detrimental to a stable pH reading. If constantly used at high temperatures, the electrode life is drastically reduced. [. . . ]